Operating mechanism for safety switch



.ugn 29, 967 'rv 1 RYS ETAL 3,339,047

OPERATING MECHANISM FOR SAFETY SWITCH Filed July l2, 1965 4 Sheets-Sheetl (QJ. @i 50 Allg 29, 9$7 T. J. RYs ETAL OPERATING MECHANISM FOR SAFETYSWITCH Filed July l2, 1965 Allg. 29, 1967 T RYS ETAL 3,339,947

OPERATING MECHANISM FOR SAFETY SWITCH Filed July l2, 1965 4 Sheets-Sheet5 Aug., E? T. J, Rvs ETAL. 3,33%@47 OPERATING MECHANISM FOR SAFETYSWITCH Filed July l2, 1965 4 Sheets-Sheet 4 United States Patent O3,339,047 OPERATING MECHANISM FOR SAFETY SWITCH Tadeusz .1. Rys andHarris I. Stanback, Lexington, Ky., assignors to Square D Company, ParkRidge, Ill., a corporation of Michigan Filed July 12, 1965, Ser. No.471,212 14 Claims. (Cl. 200-153) ABSTRACT OF THE DISCLOSURE A safetyswitch including a blade actuating member pivotable to move switchblades between ON'and OFF positions and an operating member pivotable tomove the blade actuating member. There are two operative connectionsbetween the operating member and the blade actuating member during theirmovement from their positions corresponding to the ON position of theswitch blades toward their positions corresponding to the OFF positionof the switch blades.

This invention relates to operating mechanisms for multipole safetyswitches, and more particularly to an operating mechanism for amulti-pole safety switch of relatively large current capacity.

In such switches, the switch blades must be clamped very tightly by thestationary contact jaws in the ON position of the blades to provideelectrical connections of low resistance, and hence a relatively largeovercenter spring is required to provide snap action. The large springmust be cocked before snapping over center to open the switch, andfrequently design considerations limit the length and arc of movement ofthe pivotable operating handle. l

When such a relatively large safety switch is provided with aconventional operating mechanism including a pivotable bail member foroperating the switch `blades and an operator for the bail memberoperated conjointly by an operating handle and an overcenter spring andhaving only one operative connection to the bail member, eX- cessiveforce is required to move the handle from the ON to the OFF positionthereof, due to the shortness of the handle, the relatively large amountof friction between the switch blades and the stationary contact jaws,.and the relatively large spring force exerted on the operator for thebail member.

An object of the invention is to provide an improved operating mechanism`for multi-pole safety switches.

Another object is to provide an operating mechanism for a safety switch,Athe operating mechanism having a greater mechanical advantage thanprior operating mechanisms.

A further object is to provide a safety switch operating mechanismhaving a pivotable blade actuating member, an operator for pivoting theblade actuating member, an overcenter spring for pivoting the operator,an operating handle for initially pivoting the operator and charging theovercenter spring, and two separate operative connections between theoperator and the blade ac* tuating member, the purpose of the additionaloperative connection (in excess of the customary single operativeconnection between the operator and the blade actuating member) being toincrease the mechanical advantage as an aid to overcoming staticfriction when the switch blades are initially moved toward OFF positionfrom the fully ON position.

Otherobjects will become apparent when the following specification isconsidered along with the accompanying drawings, in which:

FIG. 1 is a fragmentary front elevational view of a safety switchconstructed in accordance with the inven- 3,339,047 Patented Aug. 29,A1967 tion, the cover being closed, and the handle and other parts of theoperating mechanism being in ON position;

FIG. 2 is a fragmentary side elevational view of the safety switch ofFIG. 1;

FIG. 3 is a fragmentary sectional view taken generally along the line 33 of FIG. 1, the cover being omitted;

FIG. 4 is a perspective view of the latch member for the cover of theswitch of FIG. 1;

FIG. 5 is a fragmentary front elevational view of the switch of FIG. 1,the cover being omitted;

FIG. 6 is a fragmentary side elevational view of the switch of FIG. l, aportion of a side wall of the box being broken away, and the handle andother parts of the operating mechanism being in ON position;

FIG. 7 is a fragmentary sectional view taken along the line 7 7 of FIG.6,'

FIG. 8 is a fragmentary perspective View of the blade actuating memberof the switch of FIG. l;

FIG. 9 is a view similar to FIG. 6, the handle and other parts of theoperating mechanism being in OFF position;

FIG. 10 is a perspective view of the operator for the blade actuatingmember of the switch of FIG. l;

FIG. 11 is a perspective View of a frst mounting bracket and pivot pinfor the blade actuating member of the switch of FIG. 1;

FIG. 12 is a perspective view of a second mounting fbracket and pivotpin for the blade actuating member of the switch of FIG. l;

FIG. 13 is a fragmentary sectional view taken 4generally along the lines13-13 of FIG. 15, the operator for the blade actuating member beingincluded, and the switch blades, blade actuating member, and operatorbeing in ON position;

FIG. 14 is a view similar to FIG. 13, the switch blades, blade actuatingmember, and operator being in OFF position;

FIG. l5 is a fragmentary front elevational View of the switch of FIG. 1;and

FIG. 16 is a perspective view of a bearing member which supports a pivotpin for the handle and the operator of the switch of FIG. 1.

FIGS. 1 and 2 show a safety switch constructed in accordance with theinvention and including a :box 20 having a flanged front cover 22pivotally-rnounted on a left side wall thereof as viewed in FIG. 1.Secured to a rear wall 20a of the box 20 are a pair of insulating basemembers 24 and 25, the base member 25 being best shown in FIG. 15.

As shown in FIG. 15, three mounting means 26 of the type disclosed incopending application, Ser. No. 464,348, filed on June 16, 1965, nowPatent No. 3,287,533, issued Nov. 22, 1966, and three electricalconnectors 28 of the type disclosed in copending application, Ser. No.464,336, tiled on June 16, 1965, are secured to the base member 25. Eachmounting means 26 has ya switch blade 30 pivotally mounted thereon `andincludes a pair of plug-in jaws 26a for receiving a blade-shapedterminal at one end of a cartridge fuse (not shown), as disclosed in thefirst aforesaid application. Each connector 28 on the base member 25includes a pair of plug-in jaws 28a for receiving a respective one ofthe switch blades 30 in the ON position thereof and a socket screw 32for clamping a wire-type electrical conductor in the connector, asdisclosed in the second aforesaid application. The base member 24 is ofconventional construction, it being understood that three electricalconnectors 28 are also provided on the base member 24 and that theplug-in jaws thereof respectively receive blade-shaped terminals at theother ends of the aforementioned cartridge fuses.

The base member 25 is secured to the rear wall 20a by generally A 34dand 34e adapted to tit in corresponding slots in the base member 25, asshown in FIG. l5, a straight tab 341 bent at assembly to extend over aport-ion of the base member 25, and a pair of tabs 34g and 34h which actas stops for a blade actuating member 36 to be described.

A pivot pin 38 for the blade actuating member 36 is secured to the bodyportion 34e.

The bracket 3S includes a mounting flange 35a having a pair of holes 35b(only one of which is shown in FIG. l2) for the reception of a pair ofthe screws 33, and a body portion 35e having a tab 35d adapted to t in acorresponding slot in the base member 25, a straight tab Sf bent atassembly to extend over a portion of the base member 25, and a pair oftabs 35g and 35h which act as stops for the blade actuating member 36. Apivot pin 40 for the blade actuating member 36 is secured to the bodyportion 35e.

The blade actuating member 36 is best shown in FIGS. 8 and 15 andincludes a straight elongated blade-'driving portion 36a, a Iirststraight mounting leg portion 36h extending generally at a right angleto the blade-driving portion 36a adjacent one end thereof and having ahole 36C therein for the reception of the pivot pin 3S, and a second legportion 36d extending `generally at a right angle to the blade-drivingportion 36a adjacent the other end thereof. The member 36 is preferablyformed from ilat stock, and the blade-driving portion 36a is stiffenedby formation thereof into a generally horseshoe-shaped cross section forthe greater portion of its length and exclusive only of a pair ofstraight end portions 36e and 36j. rThe leg portion 36d serves as amounting leg and is provided with a hole 36g for the reception of thepivot pin 40, the hole 36g being aligned with the hole 36C. In additionthe leg portion 36d serves as a driving leg and is provided with anoffsetting portion 36h which extends generally parallel to the endportion 36j of the bladedriving port-ion 36a. The end portion 36]c andthe offsetting portion 36h cooperate with a plate-type operator 42,

to be described, to provide a two-way driving connection between theoperator 42 and the blade actuating Imember 36. In accordance with theinvention, the leg portion 36d is longer than the leg portion 36in andincludes an extension 36j having a bent free end portion 36k cooperablewith the operator 42 to provide an ,additional driving connection, shownas a one-way driving connection in the embodiment of the inventionillustrated, between the operator 42 and the blade actuating member 36.A generally U-shaped insulator 37 is trapped between the bladedrivingportion 36a and the switch blades 30, which have correspondingly shapedinner edge portions.

The plate type operator 42 is best shown in FIG. l0 and includes a pairof spaced jaw portions 42a and 42]: which cooperate respectively withthe end portion 36jc and the offsetting portion 36h to provide theaforementioned two-way driving connection, a portion 42C for engagingthe portion 36k to provide the aforementioned one-way drivingconnection, and an olf-set tongue portion 42d coope-rable with a latchmember 44, to be described, to prevent release of t-he latch member 44and opening of the cover 22 when the switch blades 30 are in ONposition. The operator 42 is provided with a non-circular hole 42e forreception of a pivot pin 46 to be described, an arcuate slot 42]c `forconnection of the operator 42 to an operating handle 48 to be described,and a T-shaped slot 42g opening to an edge of the operator 42 forreception of a driving pin 50 of an overcenter spring mechanism to bedescribed.

As best shown in FIGS. 2 and 5, a portion of a right side wall 20h ofthe box 20 is outwardly oiset to provide a generally triangular pocket20c in which the handle 48 is pivotable. The inside of the pocket 20c isclosed by a plate member 52 best shown in FIGS. 3, 6 and 9 and securedto the side wall 2Gb in any suitable manner, as by a plurality of rivets53. As `shown -in FIGS. 5 and 7, the plate member 52 is provided with anoff set portion 52a which forms a pocket in which the latch member 44 isreceived, a pair of foot portions 52h which extend closely adjacent andgenerally parallel to the rear wall 20a and act as stops respectivelylimiting pivotal movement of the operato-r 42 in opposite directions,and a tongue 52C normally extending through a complementary slot in thecover 22 and having a hole 52d for reception of a padlock.

Secured to the inner side of the plate member 52 as by a plurality ofrivets 54 (FIGS. 6 and 9) is a bearing member 56 for an innersmall-diameter shank portion of the pin 46. The oifset portion 20c ofthe side wall 2Gb of the box 20 forms a bearing for an outerlarge-diameter head portion of the pin 46, the head portion beingprovided with a screw driver slot as shown or with equivalent turningmeans, such as a pair of opposed fiat surfaces engageable by a wrench.The operator 42 is keyed to the pin 46 for rotation integrallytherewith, and the inner end of the pin 46 is peened over.

The operating handle 48 is pivotally mounted on the pivot pin 46 and isprovided with a driving tongue 48a best shown in FIG. 7 and extendinginto the slot 42]c of the operator 42.

The latch member 44 is best shown in FIG. 4 and is provided with alatching tongue 44a which normally overlaps a portion of the outer faceof the cover 22 when the cover is closed and With an interlock tongue44b which normally cooperates with the tongue portion 42d of theoperator 42 when the switch blades 30 are in ON position. The latchmember 44 is also provided with a hole 44C for the reception of the pin`46, an elongated arcuate slot 44d for the reception of the drivingtongue 48a, and a hole 44e for the reception of a padlock. The pin 46 isrotatable relatively to the latch member 44, but rotary movement `of thelatch member 44 is prevented due to the location of the interlock tongue44b in an appropriate slot in the plate member 52, as shown in FIGS. 3,6, and 7. The slot 44d is long enough to accommodate movement of thedriving tongue 48a through the full range of pivotal movement of thehandle 48 from OFF to ON position. The plate member 52 is provided witha slot 52e (FIG. 3) corresponding to and aligned with the slot 44d. Whenthe switch blades 30 are in OFF position, the free end portion of thelatch member -44 is movable toward the oifset portion 20c of the sidewall 2Gb to move the latching tongue 44a out of latching relationshipwith the cover 22. However, when the switch blades 30 are in ONposition, the tongue portion 42d of the operator 42 is normally alignedwith the interlock tongue 44b as shown in FIGS. 3, 6, and 7, to restrainthe moving of the outer end portion of the latch member 44 and preventthe moving of the latching tongue 44a out of latching relationship withthe cover. To defeat the interlock, a knowledgeable person may rotatethe pin 46 to move the tongue portion 42d out of alignment wit-h theinterlock tongue 44b and thus allow the outer end portion of the latchmember 44 to be moved, and the latching tongue 44a to be moved out oflatching relationship with the cover, even though the switch blades 30are in ON position.

The driving pin 50 of the cvercenter spring mechanism is carried in aforked end portion of a two-part driving arm 58 (FIGS. 5 and 6i) theother end portion of which is pivotally and reciprocably -guided in abracket member 60 secured to the side wall 20b as by a pair of rivets62. A compression spring 64 surrounds the driving arm 58 and seats atone end on the bracket 60 and at the other end on a collar 66 providedon the driving arm 58.

The operating handle 48 is biased selectively toward its fully ON andfully OFF positions by a torsion spring 68 having one end portionpivotally anchored in the handle 48 and the other end portion pivotallyanchored in the bearing member 56.

The bearing member 56 is best shown in FIG. 16 an-d includes a raiseddome portion 56a and a flange portion 56b, a portion 56C of the flangeportion 56b being offset in the direction the dome portion 56a extendsfrom the remainder of the ange portion `5611. The portion 56C is offsetto provide sucient room for the spring 68 between the handle 48 and thebearing member 56, and is provided with a hole 56d for the reception ofthe respective end portion of the spring 68. The dome portion 56a isprovided with a hole 56e for the reception of the pin `46. The flangeportion 56b is provided with three holes 56f for the reception of therivets 54, and is cut away at 56g in the path of the handle portion 48a.

Operation When the operating handle 48 is moved from OFF to ON position,the switch operates in a conventional manner in that the driving tongue48a engages the operator 42 and pivots it from the position shown inFIG. 9 while charging the spring 64. The sudden release of the spring 64as the line of action thereof passes over the pivotal axis of the pin 46effects the driving of the operator 42 to ON position by the driving arm58 and driving pin S0, and the movement of the switch blades 30 to ONposition by the operator 42 and the blade actuating member 36, the jawportion 42a engaging the end portion 361 of the blade-driving portion36a.

In accordance with the invention, when the operating handle 48 is movedfrom ON to OFF position, the driving tongue 48a engages the operator 42and pivots it from the ON position shown in FIG. 6 while charging thespring 64. As the operator 42 is moved toward OFF position, the portion42e thereof engages the portion 36k of the blade actuating member 36 andpivots the blade actuating member 36 to effect the initial movement ofthe switch blades 30 toward OFF position. It will be noted that therelatively short distance of the portion 36k from the pivotal axis ofthe pin 46 results in a considerable mechanical advantage useful inovercoming the static friction between the switch blades 30 and the jaws28a. Before the switch blades 30 are completely disengaged from the jaws28a, the line of action of the spring 64 passes over the pivotal axis ofthe pin 46 and the release of the spring 64 effects the driving of theoperator `42 to OFF position by the driving arm 58 and driving pin 50,and the movement of the switch blades 30 to OFF position by the operator42 and the blade actuating member 36. Preferably the line of action ofthe spring 64 passes over the pivotal axis of the pin 46 before the jawportion 42b engages the offsetting portion 36h, and the jaw portion 42bstrikes the offsetting portion 36h with a hammerblow effect to increasethe 'speed of disengagement of the switch blades 30 from the jaws 28a;The relatively short distance of the portion 36k from the pivotal axisof the pin 46 should be compared with the relatively long distance ofthe offsetting portion 36h from the pivotal axis of the pin 46. Aconventional switch having a single operative connection between theoperator 42 and the blade actuating member 36 has a mechanical advantageproportional to the reciprocal of the relatively long distance of theoffsetting portion 36h from the pivotal axis of the pin 46, while aswitch constructed in accordance with the invention and having twooperative connections between the operator `42 and the blade actuatingmember 36 has a mechanical advantage proportional to the reciprocal ofthe relatively short distance of the portion 36k from the pivotal axisof the pin 46. In the instant case, the additional operative connectionlbetween the operator 42 and the blade actuating member 36 increases themechanical advantage over two and one-half times what it would be with asingle operative connection. This is of operator for said bladeactuating member,

considerable practical importance when the length and arc of movement ofthe operating handle are limited by the geometry of the design of theswitch and the amount of static friction between the switch blades andplug-in jaws is large. The mechanical advantage in the instant ca'se isfurther increased by the ratio of the distances of the portion 36k andthe offsetting portion 36h from' the center of the pivot pin 40,resulting in a total increase of mechanical advantage of about fourtimes that ofl a conventional switch.

It will be seen that we have provided Ia switch operating mechanismhaving improved mechanical advantage effected by the provision of twoseparate operative connections between a blade acutating member and anoperator therefor.

Various modifications may be made in the structure disclosed withoutdeparting from the spirit and scope of the invention.

We claim:

1. A safety switch comprising a switch blade pivotable between ON andOFF positions, a pivotable blade actuating member, means operativelyconnecting said blade actuating member and said switch blade, apivotable and means providing two operative connections between saidoperator and said blade actuating member during movement of saidoperator and said blade actuating member from their respective positionscorresponding to the ON position of said switch blade toward theirrespective positions corresponding to the OFF position of said switchblade.

2. A safety switch as claimed in claim 1, wherein said two operativeconnections become effective successively as said operator is pivoted tomove said blade from said ON position to said OFF position.

3. A safety switch as claimed .in claim 1, wherein said two operativeconnections between said operator and said blade actuating member are onopposite sides of the pivotal axis of said blade actuating member.

4. A safety switch as claimed in claim 1, wherein said two operativeconnections between said operator and said blade actuating member are onopposite sides of the pivotal axis of said operator.

5. A safety switch as claimed in claim 1, wherein said two operativeconnections between said operator and said blade actuating member are onopposite sides of the pivotal axis of said blade actuating member and onopposite sides of the pivotal axis of said operator.

6. A safety switch as claimed in claim 1, wherein the pivotal movementof said operator is controlled by a pivotable operating handle connectedto said operator and by an overcenter spring mechanism connected to saidoperator, and a first of said two operative connections between saidoperator and said blade actuating member becomes effective upon initialmovement of said operating handle from a position corresponding to theON position of said switch blade toward a position corresponding to theOFF position of said switch blade to charge said overcenter springmechanism and to pivot said operator and said blade actuating member`and initially move said blade from said ON position toward said OFFposition, and a second of said two operative connections between saidoperator and said blade actuating member becomes effective after theinitial movement of said blade toward said OFF position.

7. A safety switch as claimed in claim 1, wherein the pivotal movementof said operator is controlled by a pivotable operating handle connectedto said operator and by an overcenter spring mechanism connected to saidoperator, and a first of said two operative connections between saidoperator and said 4blade actuating mem-ber becomes effective uponinitial movement of said operating handle from ra position correspondingto the ON position of said switch blade toward a position correspondingto the OFF position of said switch blade to charge said overcenterspring mechanism and to pivot said operator and said blade actuatingmember and initially move said blade from said ON position toward saidOFF position, and a second of said two operative connections betweensaid operator and said blade actuating member becomes effective upondischarge of said overcenter spring mechanism to pivot said operator andsaid blade actuating member and move said blade fully to said OFFposition.

8. A safety switch comprising a plurality of generally flat switchblades disposed in flatwise parallel relationship to each other andpivotable between ON and OFF positions about .a common pivotal axis, ablade actuating member including a straight elongated blade-drivingportion and a pair of leg portions respectively extending substantiallyat right angles from said blade-driving portion adjacent opposite endsthereof, meanscperatively connecting said blade-driving portion and saidswitch blades, means mounting said leg portions for pivotal movementabout an axis substantially coaxial with theA pivotal axis of saidblades, -a pivotable operator for said blade actuating member injuxtaposed relationship to one of said leg portions on the opposite sidethereof from the other of said leg portions, an operating handlepivotable between ON and OFF positions corresponding to the ON and OFFpositions of said switch blades, means operatively connecting saidhandle and said operator, an overcenter spring mechanism, meansoperatively connecting said overcenter spring mechanism and saidoperator, means providing a first operative connection between saidoperator and said blade actuating member during movement of saidoperator and said blade actuating member from their respective positionscorresponding to the ON position of said switch blades toward theirrespective positions corresponding to the OFF position of said switchblades, and means providing a second operative connection between saidoperator and said blade actuating member during movement of saidoperator and said blade actuating member from their respective positionscorresponding to the ON position of said switch blades toward theirrespective positions corresponding to the OFF position of said switchblades.

9. A safety switch as claimed in claim S, wherein said first operativeconnection between said operator and said blade actuating member becomeseffective as said handle is initially moved from the ON position thereoftoward the OFF position thereof to initial-ly move said switch bladesfrom the ON position thereof toward the OFF position thereof and tocharge said overcenter spring mechanism, and said second operativeconnection between said operator and said blade actuating member becomeseffections extending generally parallel tive 4after initial movement ofsaid switch blades toward` the OFF position thereof.

10. A safety switch as claimed in claim 8, wherein said first operativeconnection between said operator and said blade actuating member becomeseffect-ive as said handle is initially moved from the ON positionthereof toward the OFF position thereof to initially move said switchblades from the ON position thereof toward the OFF position thereof andto charge said overcenter spring mechanism, and said second operativeconnection between said operator and said blade 4actuating memberbecomes effective upon discharge of said overcenter spring mechanism tomove said switch blades fully to the OFF position thereof.

11. A safety switch as claimed in claim 8, wherein said first and secondoperative connections between said operator and said blade actuatingmember are on opposite sides of the pivotal axis of said one legportion.

12. A safety switch as claimed in claim 8, wherein said first and secondoperative connections between said operator and said blade actuatingmember are on opposite sides of the pivotal axis of said operator.

13. A safety switch as claimed in claim 8, wherein said first and secondoperative connections between said operator and said blade actuatingmember are on opposite sides of the pivotal axis of said one leg portionand on opposite sides of the pivotal axis of said operator.

14. A safety switch as claimed in claim 8, wherein said operator is agenerally flat plate member, said one leg portion is shaped to prov-idea pair of first and second porto said elongated bladedriving portion anddisposed on opposite sides of the pivotal axis of said one leg portion,said operator has a first portion engageable with said first portion ofsaid one leg portion to provide said first operative connection betweensaid operator and said blade driving member, and said operator has asecond portion engageable with said second portion of said one legportion to provide said second operative connection between saidoperator and said blade driving member.

References Cited UNITED STATES PATENTS 1,685,234 9/1928 iKatcher200-50.1

Rosi-:RT K. SCHAEFFER, Primary Examiner.

H. BURKS, Assistant Examiner.

1. A SAFETY SWITCH COMPRISING A SWITCH BLADE PIVOTABLE BETWEEN ON ANDOFF POSITION, A PIVOTABLE BLADE ACTUATING MEMBER, MEANS OPERATIVELYCONNECTING SAID BLADE ACTUATING MEMBER AND SAID SWITCH BLADE, APIVOTABLE OPERATOR FOR SAID BLADE ACTUATING MEMBER, AND MEANS PROVIDINGTWO OPERATIVE CONNECTIONS BETWEEN SAID OPERATOR AND SAID BLADE ACTUATINGMEMBER DURING MOVEMENT OF SAID OPERATOR AND SAID BLADE ACTUATING MEMBERFROM THEIR RESPECTIVE POSITIONS CORRESPONDING TO THE ON POSITION OF SAIDSWITCH BLADE TOWARD THEIR RESPECTIVE POSITIONS CORRESPONDING TO THE OFFPOSITION OF SAID SWITCH BLADE.